Die head for cutting tapered threads



Dec 11, 1928,

H. T. SHEARER DIE HEAD FOR CUTTING TAPERED THREADS Filed May 5, 1925 2 Sheets-Sheet 1 3 n 0011* 0'0 Harry TS/zearer Dec. 11, 1928. 1,695,158

H. T. SHEARER DIE HEAD FOR CUTTING TAPERED THREADS Filed May 5, 1925 2 Sheets-Sheet 2 gn-uc-n ro'a Harry 775/120?!" Patented Dec. 11, 1928.

um'rsu STATES PATENT OFFICE.

BARB I T. B, 01 WAYNESBOBO, PENNSYLVANIA, ABSIGNCB 1'0 LANDIS MA- OHINECOKPANY, OI WAYNE BBOBO, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIL.

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" Application "area lay a, 1m. Serial no. sales.

My said invention relates to a die head and it is an object thereof to provide a head with automatic means for varying the opening between the chasers to produce a tapered thread.

Referring tothe accompan mg drawings, which are made a rt hereo and on which similar reference aracters indicate similar arts I P Fi 1 is a face view of the head with one o aser holder omitted,

Fi re 2,. a side elevation of the head 1n cl position,

' Figure 3, a similar elevation of the head in open position with parts broken away to illustrate the interior structure,

Figure 4 a similar view of the head as it is about tobe opened,

Figure 5, a longltudmal sectlon of the same,

Figure 6 is a section of a chaser and 1ts holding means, and

Figure 7 is a similar section of a different chaser and its holdin means.

In the drawin re erence character 10 1ndicates ahead bo in which trunnions 11 are mounted for osclllation. Chaser holders 12 are secured to the trunnions, these chaser holders being here shown as provided wlth tangential chasers 13 of the well-known end sharpened Landis type and bemg held in place by clamps 14 secured by screws 15. i

A rin 16 is mounted foroscillation at the forwar end of the head bod and said rin carries ins 17 connected to t e chaser hol ers by b ocks 18 slidable in slots in said chaser holders. The ring is provided at one side with an abutment 19 havin oppositely 1nclined cam faces 20 and 21. The ring is held against forward movement on the head body by means of a narrow ring 16 secured in wellknown manner to the head body.

At the rear side of the ring 16 a ring 22 is connected to the head body by means of a worm 23 having threaded engagement with the head body 10 engaging threads at 24 on the head body. This structure is old in the art'as is shown in a patent to Landis 948,893. This worm serves toadjust the ring 22 about the head body together with certain parts rotatable about the head body with said ring. The ring 22 has an outwardly projecting flange 25 which is of equal diameter with the ring 16. At its rear side the ring 22 abuts against a shoulder on the head body which shoulder with the ring 16 serves to confine rings 16 and 22 in place.

An outer'rin 26 surrounds the ring 22 and has a forwardfy extending flange which in certain positions surrounds the rings 16 and 25. The ring 26 is movable axially relatively to the head and is guided in such movement by pins 27 secured in flange 25 of rin 22. One or more screws as shown at 28 may ave threaded engagement with the ring 25. Heads at the rear ends of screws 28 are rovided with flanges (or'separate washers to move in recesses in the smaller part of ring 26 the flanges engagin shoulders at the bottom of the recesses for imiting the rearward movement of said ring.

The ring 26 is reduced in diameter at its rear end to receive a collar 29 having lateral projections 30 (Fig. 1) said projections havmg openin to receive rods which may be attached to t e work to move therewith. The

collar 29 is secured to the rings 26 by means of flat rings 31 held in place b screws 32.

An abutment 33 is secure to the ring 26 adjacent the abutment 19, the ring 26 being cut away to permit the cam faces 34 and 35 on the last-named abutment to engage the respective cam faces on the abutment 19 and for convenience the abutment 33 is hereinafter 'referredto as a cam and the abutment 19 as a follower since obviously one of the devices might be formed as a cam and the other might be variously formed as a cam follower without itself having any cam function.

.In the operation of my device the parts will be positioned as shown in Fi re 2 and in the present instance such position of parts will adjust the head for cutting from the larger end of a tapered thread to the smaller end. Any convenient arran ment such as may be had by means of r0 connected at one end to the arms 30and at the other end to the work may be made for insuring relativelongitudinal movement of the head body and the ring 26. As the cutting operation now begins the rings 26, 29 and 31 will move longitudinally relatively to the head body and therefore the abutment 33 will move relatively to the abutment 19 wherefore the cam face 34 will move along the cam face 20 until it reaches the position shown in Figure 4 whereupon the point of the follower will pass under that of the cam after which the cam face 35 will travel along cam face 21 to the position indicated in Figure 3. The effect of this relative movement of the cam and 01- 1ower is that first the space between the chasers gradually and progressively decreases so as to cut from the larger end of the taper down to the smaller, after which the relatively steep faces 35 and 21 permit the ring to move rapidly toward the-position corresponding to the open position of the head. At this time the back pressure of the work on the chasers acts through the chaser holders and the train of connections including the head body 10, the ring 25, pins 27, ring 26, abutments 33 and 19 and ring 16 to open the head and relieve the thrust of the chasers. At this time the springs 36 also cooperate to open the head, these springs being of wellknown form and forming no part of the present invention.

In closing the head it will be understood that the forward radial face of the ring 26 can normally be brought up adjacent to the rear radial face of the flange 25 of ring 22 and if no special provision were made to avoid such a contin ency that the ordinary pro er closed position of the head might easi y be made inaccurate due to the resence of small chips of metal or the like etween said faces. In order to obviate this difliculty I have provided pins 37 in the respective members with heads 38 each projecting in a position to engage a head on the opposite face whereby said faces, when the head is closed, are spaced from one another to such an extent that any sli ht amount of foreign matter between the faces will not interfere with the correct operation of the device.

In Figure 6 I have shown a cross-section of a chaser-holder 12 and a chaser 13 with its clamp 14. The face 39 of the holder on which the chaser rests is parallel to the axis of the head and at a right angle to the face of the die head. The chaser 13 is ta ered to incline it to the face of the head or cutting a tapered thread. To make the relations of parts clear I have drawn a line a parallel to the face of the chaser, a line 6 parallel to the face of the holder on which the chaser rests, and a line 0 along the axis of the clam screw. Lines 6 and c are parallel to eac other but line a is inclined as the taper of the staybolt head or other device being threaded by the chasers.

Fi re 7 shows a chaser holder 12 with a face inclined to the axis of the head and at an obtuse angle to the face of the head. A

arallel chaser 13' (one having its cutting ace parallel to its under face) is held on the face 40 of the holder by a clamp 14. Lines 0, b and 0 show the face 40 to be out of parallelism with the axis of the clamp screw but parallel to the grooved face of the chaser.

This permits milling from a flat piece of tool steel and results in a much lower cost of production than the form shown in Figure 6.

It will be understood by those skilled in the art that my device may be changed in chasers thereon, a ring movable axially of the head, means coacting therewith to open and close the head, a flange on the adjusting ring for limiting the movement of the ring in a direction to close the head and spacing means between the axially movable ring and the flange, substantially as set forth.

2. In a die head, a head body, an adjusting ring and a closing ring surrounding said body, a series of chaser holders, on said head body and said closing ring, tangential chasers adjustably secured thereto, a flange on said adjusting. ring, a ring movable axially of the head, guide pins for the axially movable ring fixed to said flange, certain of said guide pins having heads to limit the movement of the ring, and means on said axially movable ring coaoting with means on said adjusting ring for moving the chasers to form a tapered thread, substantially as set forth.

3. In a-die head, a head body, chaser holders pivoted on the head body, tangential chasers on the chaser holders, an oscillatory ring mounted on the head body said ring being pivotally connected to the c aser holders, an axially movable second ring about the head body, a collar on said second ring for moving it, and abutments on the oscillatory and axially movable rings having cam engagement whereby axial movement of said second ring will produce a rotary movement to said oscillatory ring relative to said head body for progressively varying the operat1Ve S1Z6 of the head during a threading operation to produce a tapered thread, said abutments being spaced outwardly of the cylindrical surfaces of the rings, substantially as set forth.

4. In a die head, a head body, chaser holders pivoted on the head body, tangential chasers on the chaser holders, an oscillatory ring mounted on the head body, said ring being pivotally connected to the chaser holders, an abutment on the oscillato ring, a ring movable lengthwise of the hea means preventing rotation of the last-named ring relative to the body, and a cam on said last-named ring coactingl the cam and follower being so formed as to progressively close the chasers as the threading progresses to cut a taper thread of decreasing diameter, holders pivotally connected to the head and oscillatory ring respectively, thread cutters mounted on said holders, resilient means to urge the holders and cutters to open position, substantially as set forth. 7

In witness whereof, I have hereunto set my hand at Waynesboro, Pennsylvania, this fourth day of May, A. D., 1925.

HARRY T. SHEARER. 

